Indwelling needle devices are widely used for such treatments as infusion, blood transfusion, and extracorporeal blood circulation. In such treatments, leaving a metal needle inside a blood vessel may injure the blood vessel. Thus, indwelling needle devices are known that include a soft outer needle and a hard inner needle. The outer needle and the inner needle are inserted into a blood vessel of a patient in a state in which a leading end of the inner needle protrudes from a leading end of the outer needle, and then the inner needle is retracted from the outer needle, so that only the outer needle is left inside the patient. The possibility of the extant soft outer needle injuring the blood vessel of the patient is low.
FIG. 18A is a perspective view of an example of such a conventional indwelling needle device 900 (see Patent Document 1, for example) as seen from above. FIG. 18B is a perspective view thereof as seen from below. FIG. 19 is a cross-sectional view of the conventional indwelling needle device 900 taken along a vertical plane containing line 19-19 in FIG. 18A and seen in the direction of arrows 19. For the sake of convenience of description, a side that is inserted into the patient (the left side in FIGS. 18A, 18B, and 19) is referred to as a “front side”, and a side that is opposite from this side is referred to as a “rear side”.
The indwelling needle device 900 includes a shield 920 configured by a shield tube 921 that has an approximately cylindrical shape, and an outer hub 925 that is fixed to an end (front end) of the shield tube 921. A soft outer needle 930 is fixed to a front end of the outer hub 925.
A pair of wings 929a and 929b are provided on an outer circumferential face of the shield tube 921 in the vicinity of its outer hub 925 side end. The wings 929a and 929b are flexible, and can be swung up and down.
A hub 940 is inserted in an inner cavity of the shield 920 so as to be movable in a longitudinal direction (i.e., front-rear direction) of the shield 920. A hard inner needle 950 made of metal is fixed to a front end of the hub 940, and one end of a flexible tube 960 is connected to a rear end of the hub 940. The inner needle 950 and the tube 960 are in communication with each other via a longitudinal penetration path 943 that penetrates the hub 940 in the front-rear direction.
In FIGS. 18A, 18B, and 19, the hub 940 is located on the front end side of the inner cavity of the shield 920. This position of the hub 940 relative to the shield 920 is referred to as an “initial position”. At the initial position, the inner needle 950 held by the hub 940 penetrates the outer needle 930, and the leading end of the inner needle 950 protrudes to the outside from the leading end of the outer needle 930.
In order to maintain the hub 940 at the initial position, a stopper 970 is used. FIG. 20 is a perspective view of the stopper 970. An approximately semi-cylindrical insertion portion 972 and a pair of fixing portions 973 extend from an approximately semi-cylindrical base end portion 971. The insertion portion 972 is disposed between the pair of fixing portions 973, and these portions are parallel to one another.
As shown in FIG. 19, the insertion portion 972 of the stopper 970 is inserted from the rear end of the shield tube 921. When a leading end of the insertion portion 972 hits the rear end of the hub 940 and pushes the hub 940 toward the front side, the hub 940 can be disposed at the initial position. As shown in FIG. 18B, the tube 960 is partially exposed on the lower face side of the base end portion 971 of the stopper 970.
The inner needle 950 and the outer needle 930 are inserted into a blood vessel of the patient in a state in which the hub 940 is kept at the initial position. In order to maintain the hub 940 at the initial position during puncture, the stopper 970 has to be prevented from being displaced relative to the shield 920. Accordingly, an operator may grip with two fingers the base end portion 971 of the stopper 970 in the vertical direction (see arrows H91 in FIG. 18A) or in the horizontal direction (see arrows H92 in FIG. 18A), or may grip the pair of fixing portions 973 in the horizontal direction (see arrows H93 in FIG. 18A). Alternatively, the operator may bend the pair of wings 929a and 929b upward such that the pair of fixing portions 973 are sandwiched and fixed between the pair of wings 929a and 929b and the shield tube 921, and grip with two fingers the pair of wings 929a and 929b overlapping each other.
Subsequently, the stopper 970 is pulled out of the shield 920, and then the tube 960 is pulled from the shield 920. Accordingly, the hub 940 and the inner needle 950 are moved together with the tube 960 toward the rear side relative to the shield 920, and the inner needle 950 is housed within the shield 920 as shown in FIG. 21. The position of the hub 940 relative to the shield 920 shown in FIG. 21 is referred to as a “retracted position”. In this state, the indwelling needle device 910 is fixed to the patient using adhesive tape or the like. Only the soft outer needle 930 is left inside the patient in a state in which it is inserted in the patient.
Patent Document 1: Japanese Patent No. 4506834